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Delta blues

Will a plan to unshackle the Mississippi succeed? One thing's for sure, the …

Whenever the topic of Katrina's destruction of New Orleans and the surrounding area comes up, the talk turns to the loss of coastal wetlands in Louisiana and the muzzling of the mighty Mississippi. In the natural scheme of things, the river would accumulate silt in the delta, that would eventually block its flow to the sea. When a big flood arrived, instead of all that sediment washing out to sea, it would instead be pushed into the wetlands, replenishing land eroded by the sea and diverting the course of the river to another path.

The past hundred years have seen this setup altered. Instead, a series of banks, dikes and levees have been constructed that contain flooding and keep the river open for commercial traffic. Sadly, what's good for commerce isn't so good for much else. 75 square km of land are lost to the sea each year and New Orleans is subsiding at an impressive rate, with all that means for defense against hurricanes and rising sea levels. 120 million tons of nutrient-rich sediment that would alleviate these problems are instead dumped into the deep ocean. The results are huge dead zones in the Gulf, devastating marine life and destroying the livelihoods of fishing fleets.

There is of course a solution to all of this, but up until now it has not been one that's been seriously contemplated. The answer, as should be obvious, is to let the river flood:

"A major diversion in the lower part of the river is something that needs to be done," said James R. Hanchey, deputy secretary of the Louisiana Department of Natural Resources. He said the state was convening a planning meeting on the idea this fall. The diversion would be well downstream of New Orleans, in the bird-foot delta at the river’s mouth.

This would be accomplished by altering the river's path south of New Orleans by means of a barrier island. The remaining land south of the diversion point would break up and wash inland, and would help restore some of the lost wetlands, along with the aforementioned 120 million tons of silt. Although the wetlands wouldn't be restored overnight, the loss would be slowed down, and in some areas reversed. The problem of dead zones in the Gulf would also be helped, with all the benefits that would bring to the marine inhabitants and those who depend on them for their livelihoods.

There are a couple of problems with this plan, though, For one, it won't be cheap, but the same can be said for another Katrina. The other is the need to keep a navigable channel open:

People involved in the proposal recognize that the lower Mississippi is "a working landscape" that must continue to function, said James T. B. Tripp, a lawyer for Environmental Defense and a member of the Louisiana Governor’s Commission for Coastal Restoration.

"One of the major obstacles to doing any of this pre-Katrina was the navigation industry," he said. "As a result of Katrina, everyone’s thinking has become more flexible. Katrina brought all that home: how vulnerable this economic infrastructure has become. So there is a greater readiness today to think more boldly about how we can manage the river in a way that will help restore and build wetlands."

Of course the proposed project will be expensive. But Mr. Tripp said there were already "three or four" available financing sources, including coastal oil and gas revenues and other money already approved for coastal restoration.

"Is it practical? Yes," he said. "Will it be expensive? Yes. But when you look at the alternatives it’s very cost effective," particularly in an era of rising sea levels.

If the political will can be generated to take these steps to revive the wetlands and divert the river, the benefits to the region would be innumerable. For now, lets be cautiously optimistic that such a project is being considered seriously.

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